US3976500AExpiredUtility
Method for dissolving non-ferrous metals
Est. expiryAug 27, 1993(expired)· nominal 20-yr term from priority
Inventors:Earl J. Fadgen, Jr.
C23F 1/44
47
PatentIndex Score
6
Cited by
2
References
10
Claims
Abstract
Non-cyanide alkaline aqueous solutions for stripping non-ferrous metals, especially copper, from ferrous metal such as, for example, steel. The stripper solution comprises a water-soluble nitrate, a water-soluble compound of the formula ##EQU1## wherein R represents a valence bond, --CH 2 ) x wherein x is an integer of 1 to 2, ##EQU2## WHEREIN Y IS AN INTEGER OF 1 TO 2, OR ##EQU3## and M is a compatible, hydrophilic, i.e. water-loving or water-solubilizing, cation, a water-soluble persulfate, a water-soluble urea compound, and ammonium hydroxide. Brass, cadmium and zinc can also be stripped from steel by the stripper or dissolving solutions herein.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A process for stripping a non-ferrous metal from a ferrous metal substrate without any substantial attack on the ferrous metal substrate, which comprises contacting the non-ferrous metal on the ferrous metal substrate with a non-cyanide alkaline aqueous solution consisting essentially of about 15 to about 85 g/l of a water-soluble nitrate, about 0.1 to about 20 g/l of a water-soluble compound of the formula ##EQU4## wherein R is selected from the group consisting of a valence bond, --CH 2 ) x wherein x is an integer of 1 to 2, ##EQU5## wherein y is an integer of 1 to 2, and ##EQU6## and M is a hydrophilic cation, about 17 to about 220 g/l of a water-soluble persulfate, about 1 to about 65 g/l of a water-soluble urea compound, and ammonium hydroxide in amount sufficient to adjust the pH to within the range of about 9 to about 10, and maintaining the non-ferrous metal on the ferrous metal substrate in contact with said solution until the non-ferrous metal is dissolved from the ferrous metal substrate.
2. The process of claim 1 wherein the solution consists essentially of the following constituents in proportions within the proportion ranges hereafter specified: g/l
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Water-soluble nitrate (calcu-
lated as ammonium nitrate)
about 20 to about 80
Water-soluble compound of
the formula
##STR11##
wherein R is selected from the
group consisting of a valence
##STR12##
##STR13##
y is an integer of 1 to 2, and
##STR14##
cation
(calculated as ammonium
oxalate) about 0.1 to about 20
Water-soluble carbonate
(calculated as ammonium
carbonate) 0 to about 45
Water-soluble persulfate
(calculated as ammonium
persulfate about 17 to about 220
Water-soluble chloride
(calculated as ammonium
chloride) 0 to about 65
Water-soluble formate
(calculated as ammonium
formate) 0 to about 25
Water-soluble urea compound
(calculated as urea) about 1 to about 65
Water-soluble citrate
(calculated as ammonium
citrate) 0 to about 30
Ammonium hydroxide Sufficient to adjust
pH to about 9 to
about 10.
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3. The solution of claim 2 wherein the water-soluble nitrate is selected from the group consisting of nitrates of ammonium and an alkali metal, M of the formula ##STR15## is selected from the group consisting of ammonium and alkali metal cations, the water-soluble carbonate is selected from the group consisting of carbonates of ammonium and an alkali metal, and water-soluble persulfate is selected from the group consisting of persulfates of ammonium and an alkali metal, the water-soluble chloride is selected from the group consisting of chlorides of ammonium and an alkali metal, the water-soluble formate is selected from the group consisting of formates of ammonium and an alkali metal, and the water-soluble citrate is selected from the group consisting of citrates of ammonium and an alkali metal.
4. The solution of claim 2 wherein the water-soluble urea compound is urea.
5. The composition of claim 3 wherein the water-soluble nitrate is ammonium nitrate, R of the compound of the formula ##STR16## is a valence bond and M is an ammonium cation, the water-soluble carbonate is ammonium carbonate, the water-soluble persulfate is ammonium persulfate, the water-soluble chloride is ammonium chloride, the water-soluble formate is ammonium formate, and the water-soluble citrate is an ammonium citrate.
6. The process of claim 1 wherein the contacting is carried out at a solution temperature in the range of room temperature to about 120° F.
7. The process of claim 6 wherein the solution temperature is room temperature.
8. The process of claim 1 wherein the contacting is for a period of about 60 minutes.
9. The process of claim 1 wherein the contacting is by immersing.
10. The process of claim 1 wherein the non-ferrous metal is copper.Cited by (0)
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